Fluid jack with ram locking means



Dec. 7, 1948. H. E. PAGE Q 5,

FLUID JACK WITH RAM LOCKING MEANS Filed Feb. 17, 1945 Patented Dec. 7, 1948 l D STATES, PATENT carter:

2 Claims.

This invention has to do with jacks, having for its principal object theprovision of a hydraulic jack embodying novel means for positively looking the ram in elevated position.

A more particular object of the invention is the provision in a jack of novel chuck and chuckactuating means for locking the ram inelevated position.

In the use of hydraulic jacks, particularly those used for jacking up airplanes, it is highly essential that no retractive movement of the jack ram take place, although it is well known that frequently, due to faulty valves, sufficient hydraulic leakage from the work pressure chamber occurs to allow the ram to settle at least slightly, resulting in tremendous strains being set up in the airplane due to unequal load caused by settling of the ram. An expedient which has been employed to overcome this has been the threading of a nut onto the ram, which nut is spun downwardly into position against the top of the jack body after the ram is protracted to the desired height. This expedient has left must to be desired, however, because it requires considerable time to spin the nut down into locking position after the ram is elevatedthe distance sometimes being several feetduring which time some settling will take place, particularly where the valve structure of the jack is defective. Also, the threads, being exposed, become clogged with dirt and mud in actual use, thus preventing ready spinning of the nut and also the threads act as carriers to carry dirt and foreign matter into the jack body or cylinder, resulting in injury to the interior mechanism.

In general, I overcome those shortcomings of prior art jacks by employing a split collar chucking device between the ram and body, together with simple and positive means for moving the chuck into and out of locking position; the chuckactuating means, in some of the more particular aspects of my invention, taking the form of either a mechanical actuator or a fluid pressure operated actuator.

Additional features of novelty and advantage will become apparent to those skilled in the art from a consideration of the following description of presently preferred embodiments of the invention, although I wish to say at the outset that the invention in its broader aspects as defined by the appended claims is susceptible of modification within the scope of the claims. For purposes of the following description I shall refer to the accompanying drawings, in which:

Fig. 1 is a medial vertical section taken on line l-l of Fig. 2;

Fig. 2 is a top plan view; and

Fig. 3 is a sectional view, partly in side elevation, showing a conventional hydraulic pump.

Referring to the drawings, I show at 5 a jack body ;having alongitudinal bore .6 providing a ,pressure chamber C which is adapted to be charged wvith flu-id under ,pressure .from a con- .ventional ,pressure generating means :through a .portfi. anda fluidlreservoir R. flhe pr-esentgencrating means may be,,for;instanc.e, ea conventional hydraulic .p mp Such -.asilh.lstrated ln Fig. 3, and-tube therein-after-;des.cribed. -A ram I0 is mounted to -'r-.e,ciprocate;inr-the borewithits lower .EI'IQEGXHUSEd to theechamber.C andrcarries-at its top enda work.,contacting;pad 43. ,-It willzbe seen that the application of pressure to chamber C will protract or raise the ram and release of pressure from the chamber will permit the ram to retract under influence of the load.

In the top of the body, concentric with bore 6, I provide a recess I2 having a tapered annular side wall ll for the reception of a split tapered collar or collet l5 having adjacent but spaced from its top end an annular flange IS.

The body is exteriorly threaded at 2B and threadedly carries a nut 22 having at its top end portion an inwardly projecting flange 23 which overlies the collar flange It. A diametrically split plate 2t overlies the flange 23 and is secured to the top end of the collar by screws 25. From the foregoing it will be observed that the flange 23 of the nut is so confined between plate 24 and collar flange it that raising or lowering of the nut will correspondingly move the two segments constituting the collar l5.

Thus in operation, after pressure is applied to chamber C to cause the top end of the ram to engage and lift the load, the ram may be quickly locked in such elevated position by rotating the nut 22 to rotate it downwardly on the body, causing the collar 15 to be wedged between the ram and the side wall ll of the recess to positively lock the ram against settling even if pressure should leak from chamber C. To facilitate turn ing of the nut I provide a peripheral socket 28 in the nut to receive a tool used to rotate the nut. When it is desired to lower the ram the nut is rotated in the opposite direction to lift the collar from wedging engagement with the ram and recess side wall.

The pump unit shown in Fig. 3 for actuating the ram has a cylinder 2! connected through valve controlled conduit 28 with the reservoir R and through valve controlled conduit 8 with chamber C, and having reciprocably mounted in the cylinder a conventional pumping piston P actuated by the usual lever, not shown. To release pressure from chamber C to the reservoir I provide conduit 29 controlled by valve 29a. Other speci flc types of fluid pressure supply units may be substituted for that described.

I claim:

1. In a jack having an externally threaded annular body presenting a bore having a tapered outer end and a ram reciprocably mounted in the bore; means for locking the ram against axial movement inwardly of the bore, comprising a wedge-shaped chuck adapted to be axially movably mounted between the ram and the tapered outer end portion of said bore for wedging engagement therewith and an internally threaded nut for threaded engagement with the body, said nut and. chuck having interengaging flange and socket means whereby rotation of the nut relative to the body moves the chuck axially.

2. In a jack having an externally threaded annular body presenting a bore having a tapered outer end and a ram reciprocably mounted in the bore; means for locking the ram against axial movement inwardly of the bore, comprising a wedge-shaped chuck adapted to be axially movably mounted between the ram and the tapered outer end portion of said bore for wedging engagement therewith and a nut for threaded engagement with the body, said chuck having a laterally projecting flange spaced from its top end and a cap plate removably secured to its top end and having a portion projecting laterally therefrom in overhanging relation to the flange whereby to provide a space therebetween, and

said nut having a lug projecting laterally into said space.

HERBERT E. PAGE.

5 REFERENCES CITED The following references are of record in the file of this patent:

10 UNITED STATES PATENTS Number Name Date 512,313 McDonald Jan. 9, 1894 651,693 Berford June 12, 1900 689,855 Copeland Dec. 31 1901 5 1,058,679 Voight Apr. 8 l9li3 1,270,977 Schade July 2, 1918 1,938,191 Metz et al. Dec. 5, 1933 1,956,110 Turrettini Apr. 24, 1934 2,119,419 Clench May 31, 1938 20 FOREIGN PATENTS Number Country Date 166,138 Great Britain Mar. 16, 1922 423,141 Great Britain Jan. 25, 1935 25 307,220 Germany Aug. 3, 1918 81,002 Austria July 26, 1920 

